170Settings
Accounts & sync
Use the Accounts & sync settings to add, remove, and manage your GoogleTM and other supported accounts. You also use these settings to control how and whether all applications send, receive, and sync data on their own schedules and whether all applications can synchronize user data automatically.
GmailTM, Calendar, and other applications may also have their own settings to control how they synchronize data; see the sections on those applications for details.
General sync settings
Background data Checkmark to permit applications to synchronize data in the background, whether or not you’re actively working in them. Removing the checkmark can save battery power and lowers (but does not eliminate) data use.
Key 
and touch Sync now to synchronize data for that account. Synchronizing data automatically is disabled if Background data is uncheckmarked.
Manage accounts
List of all Google Accounts and other accounts you’ve added to the phone. If you touch an account in this screen, its account screen opens.
Account screen
This screen contains different options, depending on the kind of account.
For Google Accounts, it lists the kinds of data you can synchronize to the phone, with checkboxes so you can turn synchronizing on and off
for each kind. You can also press the Menu Key 
and touch Sync now to synchronize data. Touch Remove Account to remove the account along with all its data (contacts, mail, settings, and so on). You can’t remove the first Google Account you added to your phone except by resetting your phone to the factory defaults and erasing all of your user data.